DTC C1278 ETS Temporarily Inhibited By PCM. Chevrolet PJJ 2000

For 1990-2009 cars

### Circuit Description

The PCM monitors various parameters and will not allow ETS operation if any parameter falls outside a specified range.

### Conditions for Running the DTC

The ignition is ON.

### Conditions for Setting the DTC

A malfunction has been detected by the PCM which would inhibit ETS operation.

### Action Taken When the DTC Sets

• | The EBCM disables the ETS for the duration of the ignition cycle.

• | The TRAC OFF indicator turns ON.

• | The ABS will remain functional.

### Conditions for Clearing the DTC

• | The condition for setting the DTC is no longer present and the scan tool Clear DTCs function is used.

• | The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.

### Diagnostic Aids

• | Thoroughly inspect the wiring and the connectors. An incomplete inspection of the wiring and the connectors may result in a misdiagnosis, causing a part replacement with the reappearance of the malfunction.

• | If an intermittent malfunction exists, refer to Testing for Intermittent and Poor Connections in Wiring Systems.

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the ABS Diagnostic System Check? | -- | Go to Step 2 | Go to ABS Diagnostic System Check

2

1. Turn OFF the ignition.
2. Install a scan tool.
3. Turn ON the ignition, with the engine OFF.
4. With a scan tool, observe the DTC Information.

Does the scan tool display any other ABS DTCs?

--

Go to DTC List

Go to Step 3

3 | Is DTC C1278 set as a current code? | -- | Go to Step 5 | Go to Step 4

4

1. Start the engine.
2. Carefully test drive the vehicle at a speed above the specified value.

Use the scan tool in order to monitor the ABS DTCs.

3. Repeat the drive cycle sequence twice.

Did DTC C1278 set in the last 2 tests?

16 km/h (10 mph)

Go to Step 5

System OK

5 | Inspect the PCM. Refer to A Powertrain On Board Diagnostic (OBD) System Check in Engine Controls. Did you find and correct the condition? | -- | Go to Step 6 | Go to Diagnostic Aids

6

1. Use the scan tool in order to clear the DTCs.
2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

--

Go to Step 2

System OK